The invention relates to a fuel supply pump, especially for fuel presupply to an injection pump of an internal combustion engine. The fuel supply pump includes an axially movable roller shaft driven by an external cam and located in the housing of the fuel pump. A releasable mechanism secures the roller shaft within the pump housing.
The external cam used to drive fuel supply pumps of this type is usually located on the cam shaft of the fuel injection pump which is supplied with fuel by the supply pump. The fuel supply pump is usually mounted to a flange of the housing of the fuel injection pump and the roller shaft extends suitably into the housing of the fuel injection pump. However, the driving cam can be any other cam rotating at motor rpm, for example, a cam on the engine crankshaft.
The roller shafts in the fuel supply pumps of the type described above are cylindrical in cross section and thus require additional and, therefore, expensive components and manufacturing steps to secure the roller shaft against rotation and unintentional release. If no mechanism is present which releasably secures the roller shaft against unintentional release (transport security) then the roller shaft may fall into the camshaft space during installation or disassembly of the fuel supply pump and such an event can have serious attendant difficulties. On the other hand, the roller shaft must be easily demountable for purposes of repair.